Method for adhering a flexible sheet to a semi-rigid thermoplastic resinous sheet and products relating thereto

ABSTRACT

There is disclosed a method for adhering a flexible sheet (such as a fibrous or resinous sheet) to a semi-rigid thermoplastic resinous sheet (such as a polycarbonate or acrylic sheet). In one embodiment, the method comprises the steps of contacting an edge surface of a flexible fibrous sheet with a thermosetting resin and allowing the resin to cure to yield a unified surface, applying an adhesive along of an edge surface of the semi-rigid sheet to yield an adhesive surface and contacting the unified surface of the flexible fibrous sheet with the adhesive surface of the semi-rigid sheet to adhere the flexible fibrous sheet to the semi-rigid sheet. The products made by this method are suitable for a variety of applications, including use as boat and dwelling enclosures.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.08/520,929 which claims priority from co-pending Internationalapplication No. PCT/US94/14986, filed Dec. 29, 1994, and is acontinuation-in-part of pending U.S. patent application Ser. No.08/176,032, filed Dec. 30, 1993, and became U.S. Pat. No. 5,472,771 andU.S. patent application Ser. No. 08/520,929 became U.S. Pat. No.5,660,916.

TECHNICAL FIELD

This invention relates generally to a method for adhering a flexiblesheet to a semi-rigid thermoplastic resinous sheet and, morespecifically, to a method for adhering canvas to a polycarbonate oracrylic sheet.

BACKGROUND OF THE INVENTION

Canvas and other like fabrics are often used to provide protectionagainst the elements. For many products, these are the materials ofchoice for two reasons: first, they are effective in providing a shieldfrom the natural elements including wind, rain, snow and sun; andsecondly, by virtue of the soft, resilient nature of these materials,they are flexible and compactible which allows for their convenientretraction and storage. Tents and awnings, for example, havehistorically been manufactured from canvas because of the protection itprovides, and because such canvas products may be readily folded andstored when not in use.

Vehicle covers have also been fabricated from canvas-like materials formany of the same reasons. Folding tops for automobiles provide thebenefits that a convertible automobile affords. However, during periodsof cool or inclement weather, the driver is fully protected by theautomobile's convertible roof in its engaged position. Boaters may enjoysimilar protection provided by analogous covers. In addition toprotection against sun, wind and rain, boaters may also rely on thesecovers for protection of the vessel's occupants and interior against seawater during stormy or high sea conditions. For safety reasons, inaddition to providing protection against the elements, vehicle and boatcovers must also provide visibility to the operator. Typically,transparent sections are incorporated into automobile convertible tops(e.g., rear windows), as well as boat enclosures (such as a sailboatstorm dodger). These windows also provide viewing for passengers withinthe vehicle or boat.

Windows are typically made from glass. However, because glass isinflexible and unable to absorb shock, its utility as a window materialin a flexible, compactible protective enclosure is greatly diminished.Alternatives to glass primarily include flexible, resinous materials(i.e., plastics). Clear vinyl is one such plastic which has been widelyused as transparent sections or windows in these applications. Despiteits widespread application, vinyl does not share the ideal transparencyproperties of glass. Over time and use, wrinkles form in the vinyl whichreduce its visibility. Vinyl transparency is further diminished by thedifficulty associated with its cleaning. In addition, vinyl sections aresusceptible to changes in size and shape as a result of heating andcooling cycles which are commonly encountered in normal use of thesematerials as windows.

Perhaps the most durable plastics which maintain high visibility aresemi-rigid Plexiglas-type materials. These materials are characterizedby high transparency, ease of cleaning, and high shock resistance.Typical of this type of material are polycarbonate and acrylic-basedthermoplastic sheets.

The primary difficulty in manufacturing a suitable protective cover witha transparent section lies in the formation of a suitable adherence orbond between the flexible protective material (e.g., the canvas) and thesemi-rigid transparent section (e.g., the Plexiglas). This difficultyresults from the difference in the nature of the two materials. Canvasand other like fabrics are woven or otherwise composed of fibers, andpossess a porous, rough and non-uniform surface. On the other hand,typical transparent sections are resinous materials with a relativelysmooth and uniform surface.

Previous methods of joining such divergent materials include mechanicaltechniques, such as securing a transparent section in a fabric frame andattaching the frame to the body of the covering through the use of pins(U.S. Pat. No. 3,241,877). Attempts have also been made to securetransparent sections in rigid frames (U.S. Pat. No. 5,121,703).Alternatively, vinyl transparent sections have often been sewn to theflexible portion of the covering (U.S. Pat. No. 5,027,739). In theseinstances, the interface between the flexible protective sheet and thetransparent section is troublesome. Merely securing the window in afabric provides no seal against the natural elements. Moreover, the seamwhich results from sewing the two materials is susceptible to bothleakage and eventual breakdown and tearing.

Accordingly, there is a need in the art for a method for adhering canvasand like fabrics to semi-rigid transparent materials to provideflexible, protective coverings with high transparency. Furthermore, sucha method should provide a durable bond between the two materials withoutthe disadvantages associated with existing mechanical attachmenttechniques. The present invention fulfills these needs, and providesfurther related advantages.

SUMMARY OF THE INVENTION

Briefly stated, the present invention is directed to a method foradhering a flexible sheet to a semi-rigid thermoplastic resinous sheet.In one embodiment, the flexible sheet is a flexible fibrous sheet and,in another embodiment, the flexible sheet is a flexible resinous sheet.

As mentioned above, in one embodiment, the present invention is directedto a method for adhering a flexible fibrous sheet to a semi-rigidthermoplastic resinous sheet by contacting at least a portion of an edgesurface of the flexible fibrous sheet with a thermosetting resin andallowing the resin to cure to yield a unified surface, applying anadhesive along at least a portion of an edge surface of the semi-rigidthermoplastic resinous sheet to yield an adhesive surface, andcontacting the unified surface with the adhesive surface for a period oftime and under appropriate pressure to adhere the unified surface to theadhesive surface. In a preferred embodiment, the flexible fibrous sheetis a canvas material and the semi-rigid thermoplastic resinous sheet isa polycarbonate or acrylic sheet.

In another embodiment, the present invention is directed to a method foradhering a flexible resinous sheet to a semi-rigid thermoplasticresinous sheet by applying an adhesive along at least a portion of anedge surface of a semi-rigid thermoplastic resinous sheet to yield anadhesive surface, and contacting a portion of the edge surface of theflexible resinous sheet with the adhesive surface for a period of timeand under appropriate pressure to adhere the flexible resinous sheet tothe adhesive surface. In a preferred embodiment, the flexible resinoussheet is a vinyl resinous sheet and the semi-rigid thermoplasticresinous sheet is a polycarbonate or acrylic sheet.

In further embodiments of the present invention, products made by theabove methods are disclosed. These products comprise a semi-rigidthermoplastic resinous sheet having either a flexible fibrous sheet orflexible resinous sheet border affixed to at least a portion of the edgesurface thereof. Such products are useful in numerous applications,including (but not limited to) use as coverings for marine vessels andautomotive vehicles, as well as awnings for decks, porches, andrestaurant additions.

Other aspects of the present invention will become evident uponreference to the attached figures and following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a method for adhering a flexible fibrous sheet to asemi-rigid thermoplastic resinous sheet in an exploded perspective view,FIG. 1A, and in an assembled perspective view, FIG. 1B.

FIG. 2 illustrates an abraded edge surface of the semi-rigidthermoplastic resinous sheet.

FIG. 3 illustrates the process of abrading the front and back edgesurfaces of the semi-rigid thermoplastic resinous sheet.

FIG. 4 illustrates the semi-rigid thermoplastic resinous sheet afterabrading, FIG. 4A, and after smoothing the end of the abraded sheet,FIG. 4B.

FIG. 5 illustrates a representative product of this invention.

FIG. 6 presents a cross-sectional view of the product of FIG. 5.

FIG. 7 illustrates a representative product of this invention for use asan enclose for a marine vessel.

FIG. 8 illustrates a further representative product of this inventionfor use as an enclosure for a porch.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, the present invention is directed to a method foradhering a flexible sheet to a semi-rigid thermoplastic resinous sheet,and to products formed therefrom. In one embodiment, the flexible sheetis a flexible fibrous sheet, and in another embodiment the flexiblesheet is a flexible resinous sheet. Referring to FIGS. 1A and 1B, and inone embodiment, the method of this invention comprises the steps ofcontacting a portion of an edge surface 12 of a flexible fibrous sheet10 with a thermosetting resin 20 and allowing the resin to cure toprovide a unified surface 22; applying to a portion of an edge surface32 of a semi-rigid thermoplastic resinous sheet 30 an adhesive 40 toyield an adhesive surface 42; and contacting the unified surface 22 withthe adhesive surface 42 for a period of time and under sufficientconditions (e.g., temperature and pressure) to adhere the unifiedsurface to the adhesive surface, thus yielding product 50. It should benoted that the relative thickness of the individual componentsidentified in FIG. 1 are not drawn to scale. Rather, the thickness ofsome components (such as the thermosetting resin 20) has beenexaggerated to aid in the illustration thereof. In addition, due to theporous nature of the flexible fibrous sheet, the thermosetting resin 20will penetrate the edge surface 12 of the flexible fibrous sheet 10.

In a preferred embodiment of this invention, the edge surface of thesemi-rigid thermoplastic resinous sheet is abraded prior to applying theadhesive to the edge surface of the sheet. As illustrated in FIG. 2,edge surface 32 of the semi-rigid thermoplastic resinous sheet 30 isabraded by removal of a portion of the edge surface to a given depth.The abrasion of the resinous sheet effectively removes the glazedsurface of the sheet, and creates a surface which is more suitable forbonding by the adhesive.

In a preferred embodiment (as illustrated in FIG. 3), a portion of boththe front and back edge surface 32 of the semi-rigid thermoplasticresinous sheet 30 is removed by counter-rotating grinding wheels 50 and52. Preferably, the grinding wheels are about one inch in height, thusabrading the edge surface of the semi-rigid thermoplastic resinous sheeta distance extending one inch inwards from the edge of the resinoussheet. The depth of the abrading is controlled by the distance betweenthe counter-rotating wheels, and is generally set to remove about 1/32of an inch from both sides of the resinous sheet. Abrading the edgesurface to this depth removes the glazed surface of the semi-rigidthermoplastic resinous sheet, but does not significantly weaken thesheet. The depth of the abraded edge may vary, however, depending on thethickness of the semi-rigid thermoplastic resinous sheet. Similarly, theheight of the grinding wheels, and thus the width of the abraded edge,may vary depending upon the desired surface area of contact between theunified surface of the flexible fibrous sheet and the adhesive surfaceof the semi-rigid thermoplastic resinous sheet.

To protect against scratching, semi-rigid thermoplastic resinous sheetstypically are sold with a protective covering removably affixed to boththeir front and back surfaces. Preferably, this protective covering isremoved from the edge surface prior to abrading. The remaining portionof the protective covering should remain on the semi-rigid sheet untilinstallation of the completed product.

To prevent cracking of the abraded semi-rigid sheet, abraded end 34 ofthe semi-rigid thermoplastic resinous sheet 30 (see FIG. 4A) is smoothedby, for example, routing or filing. Such a smoothed abraded end 35 isillustrated in FIG. 4B. Preferably, smoothing is accomplished by passingabraded end 34 over a bullnose router bit.

The flexible fibrous sheet of this invention may be any suitableresilient and woven material. Preferred flexible fibrous sheets arecanvases which may be made from a number of closely woven fabrics,including hemp, flax, jute and cotton. Alternatively, the flexiblefibrous sheet may be made from a blend of fabrics. Suitable flexiblefibrous sheets include the following commercially available products:Sunbrella, 9.5 oz. (Glen Raven Mills); Furniture Fabrics, 8.0 oz. (GlenRaven Mills); Firesist, 9.25 oz. (Dickson Constant); Cordura 1000, 11oz. (DuPont); Cordura 4004 6/6, 6.2 oz. (DuPont); Cordura 420 6/6, 6.8oz. (DuPont); Top Gun, 11 oz. (DuPont); Anso-Tex, 10.4 oz. (AlliedSignal); Surf Craft Fabrics, 12 oz. (Doran Mills); and Weather ProofFabric, 12+ oz. (Doran Mills). In general, such flexible fibrous sheetshave a cloth weight ranging from 5 to 15 oz., preferably ranging from 6to 12 oz., and more preferably from 9 to 10 oz. In a most preferredembodiment, the flexible fibrous sheet is Sunbrella 9.5 oz. (Glen RavenMills, Glen Raven, N.C.). In addition to the companies identified above,other manufacturers of suitable fibrous sheets of this inventioninclude: Dick Elberton Company, Duran Textiles, Master Craft, TwichellCompany, and Wellenton Sears.

The semi-rigid thermoplastic resinous sheet of this invention may be anysuitable transparent or semi-transparent sheet which provides bothprotection and visibility, including resinous sheets derived fromthermoplastic resins. Thermoplastic resinous sheets are thosecharacterized by retention of their basic qualities despite repeatedheating and softening. Suitable semi-rigid thermoplastic resinous sheetsmay be derived from acrylonitrile-butadiene-styrene (ABS), acrylic,nylon, polycarbonate, polyethylene, polypropylene, polystyrene, andvinyl resins. Preferred thermoplastic resinous sheets are polycarbonate,acrylic, and vinyl resinous sheets. Suitable semi-rigid thermoplasticresinous sheets of this invention include the following Lexan sheetproducts (i.e., polycarbonates) manufactured by General ElectricPlastics (Pittsfield, Mass.): XL, 0.093-1/2 inch; Protecta Glaze,1/8-1/2 inch; Thermo Clear (twin wall sheet), 6-16 mm; MR5, 1/8-1/2inch; and Lexan Film, various gauges from 0.007-0.030 inch. Furthersuitable products are manufactured by the Rohm & Hass Company(Philadelphia, Pa.) and include: Tuffak A, film-1/2 inch(polycarbonate); Tuffak CM-2, film-1/2 inch (polycarbonate); Tuffak XL,film-1/2 inch (polycarbonate); Implex, 0.093-0.354 inch (modifiedacrylic); Plexiglass, various gauges (acrylic); Lucite, various gauges(acrylic); Acralite, various gauges (acrylic); Perspects, various gauges(acrylic); and Modified Acrylics, various gauges (acrylic). In general,such semi-rigid thermoplastic resinous sheets may range in thicknessfrom thin films up to 1/2 inch sheets, and preferably range from1/16-1/4 inches in thickness. In a most preferred embodiment, thesemi-rigid thermoplastic resinous sheet is the polycarbonate sheet LexanXL sold by General Electric Plastics (Pittsfield, Mass.).

If the semi-rigid thermoplastic resinous sheet is utilized to providevisibility, the semi-rigid thermoplastic resinous sheet should besubstantially transparent, and in a preferred embodiment is colorless.Alternatively, to provide protection against direct sunlight, thesemi-rigid thermoplastic resinous sheet may be tinted. In addition, amirrored semi-rigid thermoplastic resinous sheet may be preferred insome applications. For example, in a golf driving range setting, thedriving stalls may be separated by a mirrored semi-rigid thermoplasticsheet held within a flexible sheet. Such a product serves to isolate onegolfer from another and, by viewing his reflection in the mirroredsheet, further allows the golfer to observe his golfing stance and/orgolf club grip.

As indicated above, a unified surface is prepared along at least aportion of an edge surface of the flexible fibrous sheet. As usedherein, a "unified surface" refers to a resinous surface derived from athermosetting resin, and serves to provide a uniform, smooth andintegrated surface. The uniform and smooth surface is necessary toachieve adhesion with the adhesive surface of the semi-rigidthermoplastic resinous sheet. The unified surface is required because ofthe woven nature of the surface of the flexible fibrous sheet which isirregular and rough. Such a surface alone is unsuitable for adhering aflexible fibrous sheet to a semi-rigid thermoplastic resinous sheet. Theunified surface is also integrated with the fibrous sheet to providestrong adhesion between the unified surface and the flexible fibroussheet which, in turn, creates strong adhesion between the flexiblefibrous sheet and the semi-rigid thermoplastic resinous sheet.

The unified surface is prepared by application of a thermosetting resinto at least a portion of the edge surface of the flexible fibrous sheet.Thermosetting resins are resins which, once set at a temperaturecritical to the resin, cannot be resoftened or reworked. Suitablethermosetting resins include alkyd, epoxy, phenolic, polyester,silicone, and urethane resins. Preferred thermosetting resins are epoxyresins. In a most preferred embodiment, the epoxy resin is DP 100 (3M,St. Paul, Minn.).

With regard to the semi-rigid thermoplastic resinous sheet, the adhesivesurface is prepared by applying a suitable adhesive along at least aportion of the edge surface of the semi-rigid thermoplastic resinoussheet. As mentioned above in a preferred embodiment, the edge surfacemay be abraded prior to application of the adhesive. Suitable adhesivesinclude glues, pastes, cements, gums, resins and tapes. In a preferredembodiment, the adhesive is a double-sided acrylic, urethane,polyethylene or vinyl foam adhesive tape, and in a particularlypreferred embodiment is a double-sided adhesive acrylic foam tape. Suchacrylic foam tapes are commercially available and include very high bond(VHB) tapes such as VHB 4929, VHB 4949, and VHB 4951 (3M, St. Paul,Minn.). Preferably, the adhesive is the double coated foam tape VHB 4949having a thickness of 0.045 inches.

An important feature of the present invention is the ability to adherethe flexible sheet to the semi-rigid thermoplastic resinous sheet via aflexible bond. For example, when the adhesive is a double-sided foamtape, the bond between the flexible fibrous sheet and the semi-rigidthermoplastic resinous sheet is capable of slight movement. Suchmovement minimizes stress to the semi-rigid sheet, as well as to thebond between the adhesive surface and unified surface. In contrast, arigid bond would be relatively brittle, and would not effectivelydistribute stress to shelter the unified surface/adhesive surfaceinterface. In other words, the unified surface/adhesive surface bondallows the semi-rigid thermoplastic resinous sheet to "flout" at allpoints in contact with the flexible fibrous sheet. Thus, any materialswhich result in a unified surface and an adhesive surface which, whencontacted, yields a strong, flexible bond between the flexible fibroussheet and the semi-rigid thermoplastic resinous sheet may be used in thepractice of this invention.

In one embodiment, the products of the present invention are prepared bycontacting the unified surface of the flexible fibrous sheet with theadhesive surface of the semi-rigid thermoplastic resinous sheet. Thefirst step in the production process involves cutting a semi-rigidthermoplastic resinous sheet to size. The size of the semi-rigid sheetwill depend upon the size of the window desired in the final product.After the semi-rigid sheet has been cut to size, the perimeter or end ofthe semi-rigid sheet is smoothed either by routing or filing. Theadhesive surface is then prepared by directly applying an adhesive tothe edge surface of the semi-rigid sheet. Typically, the adhesivesurface has a dimension of one inch by the length of the resinous sheet.However, this dimension may vary depending primarily on the thickness(and thus the width) of the semi-rigid thermoplastic resinous sheet.

Alternatively, the front and/or back edge surface of the semi-rigidthermoplastic resinous sheet is abraded to provide a surface upon whichto apply the adhesive. Typically the abrasion is about one inch (1")wide and about one thirty-second of an inch (1/32") deep. Once abraded,an adhesive, such as a double-sided adhesive acrylic foam tape, isapplied to the abraded edge surface in preparation for adhesion to theflexible fibrous sheet. In a preferred embodiment, the semi-rigidthermoplastic resinous sheet is abraded along the perimeter of both itsfront and back edge surfaces and the adhesive is applied to both ofthese abraded edge surfaces. As mentioned above, the width of theabrasion may vary depending upon the application, weight of thesemi-rigid sheet and strength of bond desired.

The flexible fibrous sheet is preferably prepared for adhesion to thesemi-rigid sheet by first sizing the opening or window in the flexiblefibrous sheet within which the semi-rigid sheet will be adhered. Oncethe size of the window has been determined, that area is cut out of theflexible fibrous sheet. The cut is made in the flexible fibrous sheetsuch that the window cut out is smaller than the semi-rigid sheet (i.e.,the flexible fibrous sheet will completely overlap the abraded edgesurface of the semi-rigid sheet) . The flexible fibrous sheet ispreferably cut with a hot knife which seals the cut and prevents the cutedge from unraveling. A thermosetting resin is then applied to theportion of the flexible fibrous sheet that will overlap the adhesivesurface applied to the semi-rigid sheet. (Alternatively, thethermosetting resin may be applied to the flexible fibrous sheet priorto cutting out the window opening.) The thermosetting resin is allowedto cure to provide the unified surface. The time required for curing ofthe thermosetting resin will vary depending upon the resin used.

A representative product of the present invention is assembled bycontacting the adhesive surface of the semi-rigid sheet with the unifiedsurface of the flexible fibrous sheet. Adhesion of the flexible fibroussheet to the semi-rigid sheet is achieved by applying pressure to theoverlapping portion of the two sheets sufficient to establish uniformcontact between the adhesive surface and the unified surface. Maximumadhesion is achieved essentially upon contact and slight pressure.

In an embodiment where the semi-rigid thermoplastic resinous sheet isabraded on both its front and back edge surfaces, a second flexiblefibrous sheet is prepared as described above, and the semi-rigid sheetis "sandwiched" between the two flexible fibrous sheets. Assembly ofthis embodiment requires contacting the adhesive surfaces of thesemi-rigid sheet with the unified surfaces of both of the flexiblefibrous sheets. Such an embodiment is illustrated in FIGS. 5 and 6.

In another embodiment of the present invention, a method for adhering aflexible resinous sheet to a semi-rigid thermoplastic sheet isdisclosed. Suitable flexible resinous sheets include vinyl resinoussheets. Suitable vinyl resinous sheets include Architent, Cooley-Brite:Back-Lit Awning Fabric, Duracote, Herculite, Patio 500, Premier:Back-Lit Awning Fabric, Snyder, Stamoid (manufactured by Forbo, Inc.),Reflections: Back-Lit Awning Fabric, and Weblon. Preferred vinylresinous sheets include Duracote, Herculite, and Stamoid. Preferredweights of these vinyl resinous sheets include Duracote (16 ounces persquare yard), Herculite (10 ounces et square yard), and Stamoid (7.5ounces per square yard).

In the practice of the method of the invention, a flexible resinoussheet is adhered to a semi-rigid thermoplastic resinous sheet byapplying an adhesive along at least a portion of an edge surface of thesemi-rigid thermoplastic resinous sheet to yield an adhesive surface,and contacting a portion of the edge surface of the flexible resinoussheet with the adhesive surface for a period of time and underappropriate pressure to adhere the flexible resinous surface to theadhesive surface. As described above, the semi-rigid thermoplastic sheetmay be abraded.

Alternatively, the adhesive may be applied to the edge surface of theflexible resinous sheet to yield an adhesive surface on the flexibleresinous sheet. In this method, the semi-rigid thermoplastic sheet isadhered to the flexible resinous sheet by contacting the adhesivesurface of the flexible sheet to the semi-rigid resinous sheet.

In a preferred embodiment, the flexible resinous sheet is washed with asuitable solvent prior to contact with the adhesive surface orapplication of the adhesive. Suitable solvents include solvents whichremove surface oils from the resinous sheet and create an edge surfacewhich will have enhanced adherence to the adhesive surface of thesemi-rigid sheet or the adhesive applied to the sheet's edge surface.Suitable solvents include polar organic solvents such as acetone, methylethyl ketone, ethanol, isopropanol, and mixtures thereof. Preferably,the solvent is acetone.

For flexible vinyl resinous sheets, the adhesive is preferably adouble-sided adhesive tape. Suitable adhesive tapes include acrylictapes which are formulated to withstand a wide range of weather andtemperature conditions without losing adhesion. Preferred acrylic tapesinclude very high bond acrylic foam tapes such as VHB-4900 tapes (3M,St. Paul, Minn.), and pressure sensitive (PS) tapes such as PS-4100 andPS-4400 acrylic bonding tapes (Adco Products, Inc., Michigan Center,Mich.). Preferred VHB 4900 tapes include VHB 4945 which has a tapethickness of 0.045 inches, and preferred PS-4400 tapes include PS-4425,PS-4430, and PS-4445 which have tape thicknesses of 0.025, 0.030, 0.045inches, respectively.

In general, the products of this invention constitute a semi-rigidthermoplastic resinous sheet having a flexible sheet border. The sizeand shape of the enclosed semi-rigid sheet, as well as the size andshape of the enveloping flexible sheet border, may be widely varied.Additionally, multiple semi-rigid sheets may be enclosed within a singleflexible sheet border.

Typically, the flexible sheet also has one or more fasteners forconnection to structural elements, such as awnings or frames.Alternatively, the fasteners may facilitate joining one flexible sheetcontaining a semi-rigid sheet to another. Suitable fasteners are wellknown in the art and include zippers, grommets and pins.

The products of this invention may be used as awnings or enclosures forbuildings, as well as for convertible enclosures for marine vessels.Representative embodiments of the products of this invention are shownin FIGS. 5, 7 and 8. FIG. 5 illustrates a representative product of thisinvention with flexible fibrous sheet border 10, semi-rigidthermoplastic resinous sheet 30 and stitching 54, and having suitablefasteners such as snap 50 and zipper 52. FIG. 6 presents across-sectional view of the product of FIG. 5, depicting flexiblefibrous sheet 10, thermosetting resin 20, adhesive 40, semi-rigidthermoplastic resinous sheet 30 and stitching 54. FIGS. 7 and 8illustrate use of the product of this invention as an enclosure for amarine vessel and a porch, respectively. In addition, FIG. 7 alsoillustrates application of the product of this invention to form acurved corner window 70. In this embodiment, the semi-rigidthermosetting resinous sheet is heated and then bent to yield a curvedwindow. In this manner, products of the present invention may be used asplanar or sheet windows, as well as curved or bent windows.

The following examples are provided for purposes of illustration, notlimitation.

EXAMPLES Example 1 Method for Abrading Semi-Rigid Thermoplastic ResinousSheets

In this example, the method for abrading the front and back edgesurfaces of Lexan XL, a semi-rigid thermoplastic resinous sheet, isdescribed.

Sheets of Lexan XL are sold with a protective covering removably affixedto both front and back surfaces to prevent scratching. These sheets(with protective covering in place) are first cut to size with a saw.The protective covering over the portion of the sheet to be abraded isthen removed by scoring an appropriate distance in from the edge of thesheet, and peeling off the protective covering around the perimeter onboth the front and back surfaces of the sheet.

The Lexan XL sheet is abraded by passing the sheet betweencounter-rotating grinding wheels which are one-inch in height, thuscreating an abraded edge surface on both sides of the sheet extendingone inch along the entire perimeter of the sheet's edge. A suitableabrading device is depicted schematically in FIG. 3. The depth of theabrasion is controlled by the distance separating the counter-rotatinggrinding wheels, and is set to remove about one-thirty second (1/32") ofan inch on both sides of the Lexan XL sheet (see FIG. 4A). Afterabrading, the abraded end of the sheet is smoothed or rounded (see FIG.4B) by contact with a router having a bullnose router bit.

Abraded Lexan XL sheets prepared by the above method are suitable foradhesion to flexible fibrous sheets as described below.

Example 2 Method for Adhering a Flexible Fibrous Sheet to a Semi-RigidThermoplastic Resinous Sheet

In this example, a method for adhering a flexible fibrous sheet (i.e.,Sunbrella) to an abraded semi-rigid thermoplastic resinous sheet (i.e.,Lexan XL) is described.

Sunbrella of the size desired for the protective covering is cut with ahot knife. Once cut to size, the Lexan XL sheet prepared in Example 1above is traced upon the Sunbrella sheet at the desired window location.

The Lexan XL sheet is prepared for adhesion by creating an adhesivesurface. The adhesive surface is made by applying VHB 4949 (3M, St.Paul, Minn.), a double-sided acrylic foam tape, to all abraded surfacesof the Lexan XL sheet. The Lexan XL sheet with adhesive surface preparedin this manner is suitable for adhering to the unified surface ofSunbrella as described below.

The Sunbrella sheet is prepared for adhesion by creating a unifiedsurface on the sheet's edge surface that overlaps the adhesive surfaceof the Lexan XL sheet. The unified surface of the Sunbrella is preparedby the application of DP 100 (3M, St. Paul, Minn.), an epoxy resin. TheDP 100 resin is applied uniformly over the edge surface of the Sunbrellasheet such that coverage is complete and has a thickness betweenapproximately one-sixty fourth of an inch and one-thirty second of aninch. Once the DP 100 has been applied, the resin is allowed to cure tocreate the unified surface. Curing typically requires between six andeight hours.

The Sunbrella sheet is then cut with a hot knife along a line extendingone inch inside the perimeter of the traced window such that the unifiedsurface of the Sunbrella sheet entirely overlaps the adhesive surface ofthe Lexan XL sheet. The Sunbrella sheet with the unified surfaceprepared in this manner is suitable for adhering to the adhesive surfaceof the Lexan XL sheet as described below.

Adhesion of the Sunbrella sheet to the Lexan XL sheet is achieved bycontacting the adhesive surface of the Lexan XL sheet with the unifiedsurface of the Sunbrella sheet. Application of pressure (e.g., a roller)to the overlapped portion of the adhering surfaces assists in adhesionbetween the two sheets.

This process is then repeated to adhere a second sheet of Sunbrella tothe opposite side of the Lexan XL sheet. Once all sheets have beenadhered, the Sunbrella sheet may be trimmed to its final dimensions. Thetwo Sunbrella sheets may then be sewn together; a first seam ispreferably sewn immediately beyond the Lexan XL sheet, and a second seammay be sewn near the Sunbrella sheet's edge. To facilitate attachment ofthe Sunbrella sheet to other coverings or to structural supports,suitable fasteners are affixed to the Sunbrella sheet.

A final product prepared by the method described above is illustrated inFIG. 5. The application of the product as a protective covering for amarine vessel and a porch enclosure are illustrated in FIGS. 7 and 8,respectively.

Example 3 Method for Adhering a Flexible Resinous Sheet to a Semi-RigidThermoplastic Resinous Sheet

In this example, a method for adhering a flexible resinous sheet (i.e.,Duracote) to an abraded semi-rigid thermoplastic resinous sheet (i.e.,Lexan XL) is described.

Duracote of the size desired for the protective covering is cut with ahot knife. Once cut to size, the Lexan XL sheet prepared in Example 1above is traced upon the Duracote sheet at the desired window location.

The Lexan XL sheet is prepared for adhesion by creating an adhesivesurface. The adhesive surface is made by applying VHB 4945 (3M, St.Paul, Minn.), a double-sided acrylic foam tape, to all abraded surfacesof the Lexan XL sheet. The Lexan XL sheet with adhesive surface preparedin this manner is suitable for adhering to the edge surface of Duracoteas described below.

The Duracote sheet is prepared for adhesion by washing the resinoussheet's edge surface with acetone. Washing is accomplished by wiping alight coat of acetone with a cotton cloth along the edge to be contactedwith the adhesive.

The Duracote sheet is then cut with a hot knife along a line extendingone inch inside the perimeter of the traced window such that the acetonewashed edge surface of the Duracote sheet entirely overlaps the adhesivesurface of the Lexan XL sheet. The Duracote sheet with the acetonewashed edge surface prepared in this manner is suitable for adhering tothe adhesive surface of the Lexan XL sheet as described below.

Adhesion of the Duracote sheet to the Lexan XL sheet is achieved bycontacting the adhesive surface of the Lexan XL sheet with the acetonewashed surface of the Duracoat sheet. Application of pressure (e.g., aroller) to the overlapped portion of the adhering surfaces assists inadhesion between the two sheets.

This process is then repeated to adhere a second sheet of Duracote tothe opposite side of the Lexan XL sheet. Once all sheets have beenadhered, the Duracote sheet may be trimmed to its final dimensions. Thetwo Duracote sheets may then by sewn together; a first seam ispreferably sewn immediately beyond the Lexan XL sheet, and a second seammay be sewn near the Duracote sheet's edge. To facilitate attachment ofthe Duracote sheet to other coverings or to structural supports,suitable fasteners are affixed to the Duracote sheet.

From the foregoing, it will be appreciated that, although specificembodiments of this invention have been described herein for thepurposes of illustration, various modifications may be made withoutdeparting from the spirit and scope of the invention. Accordingly, theinvention is not limited except by the appended claims.

We claim:
 1. A method for adhering a flexible fibrous sheet to asemi-rigid thermoplastic resinous sheet comprising the stepsof:contacting at least a portion of an edge surface of the flexiblefibrous sheet wish a thermosetting resin and allowing the resin to cureto yield a unified surface; applying an adhesive along at least aportion of an edge surface of the semi-rigid thermoplastic resinoussheet to yield an adhesive surface; and contacting the unified surfacewith the adhesive surface for a period of time and under sufficientpressure to adhere the unified surface to the adhesive surface.
 2. Themethod of claim 1 wherein the flexible fibrous sheet is a canvas.
 3. Themethod of claim 1 wherein the thermosetting resin is an epoxy resin. 4.The method of claim 1 wherein the adhesive is a double-sided adhesivefoam tape.
 5. The method of claim 4 wherein the double-sided adhesivetape is an acrylic foam tape.
 6. The method of claim 1 wherein thesemi-rigid thermoplastic resinous sheet is transparent.
 7. The method ofclaim 1 wherein the semi-rigid thermoplastic resinous sheet is tinted.8. The method of claim 1 wherein the semi-rigid thermoplastic resinoussheet is mirrored.
 9. The method of claim 1 wherein the semi-rigidthermoplastic resinous sheet is selected from the group consisting of apolycarbonate resinous sheet, an acrylic resinous sheet, and a vinylresinous sheet.
 10. The method of claim 1 wherein prior to applying theadhesive to the semi-rigid thermoplastic resinous sheet, the sheet isabraded along at least a portion of the edge surface.
 11. A product madeaccording to the method of any one of claims 1-10.
 12. A method foradhering a flexible resinous sheet to a semi-rigid thermoplasticresinous sheet comprising the steps of:applying an adhesive along atleast a portion of an edge surface of a semi-rigid thermoplasticresinous sheet to yield an adhesive surface; and contacting the adhesivesurface with a portion of an edge surface of the flexible resinous sheetfor a period of time and under sufficient pressure to adhere theflexible resinous sheet to the adhesive surface.
 13. The method of claim12 wherein the flexible resinous sheet is a vinyl resinous sheet. 14.The method of claim 12 wherein the adhesive is a double-sided adhesivetape.
 15. The method of claim 14 wherein the double-sided adhesive tapeis an acrylic foam tape.
 16. The method of claim 14 wherein thedouble-sided adhesive tape is an acrylic bonding tape.
 17. The method ofclaim 12 wherein the edge surface of the flexible resinous sheet iswashed with a solvent prior to contacting the adhesive surface.
 18. Themethod of claim 17 wherein the solvent is acetone.
 19. The method ofclaim 12 wherein the semi-rigid thermoplastic resinous sheet istransparent.
 20. The method of claim 12 wherein the semi-rigidthermoplastic resinous sheet is tinted.
 21. The method of claim 12wherein the semi-rigid thermoplastic resinous sheet is mirrored.
 22. Themethod of claim 12 wherein the semi-rigid thermoplastic resinous sheetis selected from the group consisting of a polycarbonate resinous sheet,an acrylic resinous sheet, and a vinyl resinous sheet.
 23. The method ofclaim 12 wherein prior to applying the adhesive to the semi-rigidthermoplastic resinous sheet, the sheet is abraded along at least aportion of the edge surface.
 24. A product made according to the methodof any one of claims 12-23.